There are many types of steel bars. According to production technology, it can be divided into hot-rolled steel bars, cold drawn steel bars, cold drawn steel wires, carbon steel wires, scored steel wires, steel hinge wires, and heat treated steel bars, among which the latter four are mainly used in prestressed concrete engineering. According to chemical composition, carbon steel reinforcement can be further divided into carbon steel reinforcement and ordinary low alloy steel reinforcement. Carbon steel reinforcement can be further divided into three types based on its carbon content: low-carbon steel reinforcement (with a carbon content of ∠ 0.25%), medium carbon steel reinforcement (with a carbon content of 0.25-0.7%), and high carbon steel reinforcement (with a carbon content of 0.7-1.4%). Ordinary low alloy steel is a steel grade that adds a small amount of alloying elements to the composition of low and medium carbon steel to obtain high strength and good comprehensive performance. According to mechanical properties, it can be divided into HPB235 grade steel bars, HRB335 grade steel bars, HRB400 grade steel bars, and HRB500 grade steel bars, etc; Moreover, the higher the level, the higher its strength and hardness, leading to a gradual decrease in plasticity; For easy identification, different colors of paint are applied to the ends of steel at different levels. According to their appearance, they can be divided into deformed steel bars and round steel bars, with the former being divided into three types: crescent shaped, spiral shaped, and herringbone shaped. According to the supply form, in order to facilitate transportation, steel bars with a diameter of 6-10mm are usually rolled into discs, known as round or bar steel bars; Roll steel bars with a diameter greater than 12mm into a length of 6-12m, and call them straight or rolled steel bars. According to diameter, it can be divided into steel wire (diameter 3-5mm), fine steel bar (diameter 6-10mm), medium coarse steel bar (diameter 12-20mm), and coarse steel bar (diameter greater than 20mm). According to the different roles of steel bars in structures, they can be divided into load-bearing steel bars, erected steel bars, and distributed steel bars.